1. Field of the Invention
This invention relates to a technique for the union between an aluminum profile and a resin material, and more particularly to resin-composite aluminum profiles having a resin material joined to an aluminum profile, especially heat insulating aluminum profiles having the joined parts of opposed lateral sheet members of an aluminum profile formed with a resin material, a method for the production of the profiles, and an apparatus, particularly a discharge treatment apparatus to be used for the production of the profiles.
The term "aluminum profile[s]" is used herein to express the shapes or sections of aluminum or an aluminum alloy shaped into a continuous form (hereinafter referred to simply as "profile[s]") and the term "resin-composite aluminum profile[s]" is used to express the concept embracing the heat insulating aluminum shapes or sections (hereinafter referred to simply as "heat insulating profile[s]").
2. Description of the Prior Art
The composite profiles having a resin material joined to the surface or recess of a profile have been used in various technical fields because they are light and excellent in durability, strength, or the like. Particularly, in the technical field of construction, sashes which are provided on either of the exterior and the interior side of building with a double paper sliding door disposing part have been disseminating with a view to affording insulation from heat, abating noise, and preventing dew condensation. The heat insulating profiles are used in the frames of such sashes.
The heat insulating profile is provided between the opposed lateral sheet members thereof with a joined part formed of synthetic resin and, in this structure, allowed to have the opposed lateral sheet members integrally joined by the adhesive force of the resin material and, owing to the intervention of the resin material between the opposed sheet members, enabled to manifest the functions of affording insulation from heat, abating noise, and preventing dew condensation. As the resin material mentioned above, generally a foamable hard polyurethane resin is used as taught in published Japanese Patent Application, KOKAI (Early Publication) No. 54-19,537, for example.
Generally in the production of the heat insulating profile, a urethane resin material is injected to capacity into a recess provided between the coated, opposed lateral sheet members of a profile and wished to be packed with a resin and thereafter the portion of the profile which forms the recess is cut so that the opposed lateral sheet members are joined to each other solely with the urethane resin.
Since the adhesive force produced by the urethane resin is not sufficient, however, the resin and the profile are liable to peel off each other. Once the separation of this sort occurs, the profile has the problem of emitting a squeak when deformed under an external force and betraying deficiency in strength as well. Further, the heat insulating profile entails the problems of durability such as causing shrinkage of the urethane resin after a protracted use, tending to induce the phenomenon of giving rise to a step in the butt end (discernible by a test of repeating cycles of cooling and heating), and possibly inserting a crack in the face of union and inducing leakage of rain water through the crack. For the purpose of compensating the urethane resin for the shortage of adhesive force, such measures as applying a primer layer to the inner surface of the recess in the profile wished to be filled with resin or mechanically forming a multiplicity of claw parts on the inner surface have been heretofore proposed. These measures, however, entail highly expensive treatments, require introduction of expensive devices, and suffer poor productivity. These treatments are not easily performed uniformly on the inner surface of the recess, particularly so when a hole-forming part for a screw is protruded into the recess.